Light-emitting element capable of increasing amount of light emitted, light-emitting device including the same, and method of manufacturing light-emitting element and light-emitting device

ABSTRACT

A light-emitting element capable of increasing the amount of light emitted, a light-emitting device including the same, and a method of manufacturing the light-emitting element and the light-emitting device include a buffer layer having an uneven pattern formed thereon; a light-emitting structure including a first conductive pattern of a first conductivity type that is conformally formed along the buffer layer having the uneven pattern formed thereon, a light-emitting pattern that is conformally formed along the first conductive pattern, and a second conductive pattern of a second conductivity type that is formed on the light-emitting pattern; a first electrode electrically connected to the first conductive pattern; and a second electrode electrically connected to the second conductive pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No.10-2008-0090732 filed on Sep. 16, 2008 in the Korean IntellectualProperty Office, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting element, alight-emitting device including the light-emitting element, and a methodof manufacturing the light-emitting element and the light-emittingdevice.

2. Description of the Related Art

Light-emitting elements, such as LEDs (light emitting diodes), emitlight by coupling between electrons and holes. The light-emittingelement has small power consumption, a long life span, a sufficientlysmall size to be provided in a small space, and high shock resistance.

For example, the light-emitting element includes a light-emittingpattern formed between an n-type GaN pattern and a p-type GaN pattern.In the light-emitting pattern, carriers (electrons) of the n-type GaNpattern and carriers (holes) of the p-type GaN pattern are coupled toeach other to emit light.

The amount of light emitted from the light-emitting element isproportional to the size of the light-emitting pattern. That is, as thesize of the light-emitting pattern is increased, the amount of lightemitted from the light-emitting element is increased.

In the related art, a flat light-emitting pattern is formed on asubstrate. Therefore, in order to increase the size of thelight-emitting pattern, the overall size of the light-emitting devicemust be increased.

SUMMARY OF THE INVENTION

Aspects of the present invention provide a light-emitting element and alight-emitting device capable of increasing the amount of light emitted.

Aspects of the present invention also provide a method of manufacturinga light-emitting element and a light-emitting device capable ofincreasing the amount of light emitted.

The aspects, features and advantages of the present invention are notrestricted to those set forth herein. The above and other aspects,features and advantages of the present invention will become moreapparent to one of ordinary skill in the art to which the presentinvention pertains by referencing the detailed description given below.

According to an aspect of the present invention, there is provided alight-emitting element including: a buffer layer having an unevenpattern formed thereon; a light-emitting structure including a firstconductive pattern of a first conductivity type that is conformallyformed along the buffer layer having the uneven pattern formed thereon,a light-emitting pattern that is conformally formed along the firstconductive pattern, and a second conductive pattern of a secondconductivity type that is formed on the light-emitting pattern; a firstelectrode electrically connected to the first conductive pattern; and asecond electrode electrically connected to the second conductivepattern.

In one embodiment, at least a portion of the cross-section of the unevenpattern is curved. In one embodiment, the uneven pattern has asemicircular shape in a cross-sectional view.

In one embodiment, the uneven pattern includes a plurality of periodicpatterns.

In one embodiment, the uneven pattern is at least one of a dot pattern,a line pattern, and a mesh pattern.

In one embodiment, the side wall of the light-emitting structure isinclined.

In one embodiment, the width of the first conductive pattern is largerthan that of the second conductive pattern and the light-emittingpattern such that a portion of the first conductive pattern protrudesfrom the second conductive pattern and the light-emitting pattern in alateral direction. In one embodiment, the first electrode is formed on aprotruding portion of the first conductive pattern, and the secondelectrode is formed on the upper surface and/or the side wall of thelight-emitting structure.

In one embodiment, the second electrode is a reflecting electrode, andthe second electrode is formed on the upper surface and the side wall ofthe light-emitting structure.

According to another aspect of the present invention, there is provideda light-emitting element including: a conductive substrate; a firstelectrode having a bowl shape and formed on the conductive substrate; alight-emitting structure including a first conductive pattern of a firstconductivity type, a light-emitting pattern, and a second conductivepattern of a second conductivity type sequentially formed in the firstelectrode; a buffer layer formed on the light-emitting structure; and asecond electrode formed on the buffer layer. An uneven pattern is formedon the buffer layer, the second conductive pattern is conformally formedalong the buffer layer, and the light-emitting pattern is conformallyformed along the second conductive pattern.

In one embodiment, at least a portion of the cross-section of the unevenpattern is curved.

In one embodiment, the buffer layer is formed such that a portion of thesecond conductive pattern is exposed, an ohmic layer is formed on theexposed region of the second conductive pattern, and the secondelectrode is formed on the ohmic layer.

In one embodiment, the bowl-shaped first electrode includes a protrusionthat protrudes from the lower side thereof, the light-emitting structureis divided into two sides by the protrusion, and the second electrode isformed on one side of the light-emitting structure.

According to another aspect of the present invention, there is provideda light-emitting device including the light-emitting element accordingto the above aspect.

According to another aspect of the present invention, there is provideda method of manufacturing a light-emitting element, the methodincluding: forming a buffer layer having an uneven pattern formedthereon on a substrate; forming a light-emitting structure including afirst conductive pattern of a first conductivity type that isconformally formed along the buffer layer having the uneven patternformed thereon, a light-emitting pattern that is conformally formedalong the first conductive pattern, and a second conductive pattern of asecond conductivity type that is formed on the light-emitting pattern;and forming a first electrode that is electrically connected to thefirst conductive pattern and a second electrode that is electricallyconnected to the second conductive pattern.

In one embodiment, at least a portion of the cross-section of the unevenpattern is curved.

In one embodiment, the uneven pattern includes a plurality of periodicpatterns.

In one embodiment, the forming of the buffer layer having the unevenpattern formed thereon comprises: forming the buffer layer on thesubstrate; forming a mask pattern on the buffer layer; performing a heattreatment on the substrate having the mask pattern formed thereon suchthat at least a portion of the cross-section of the mask pattern iscurved; and etching the buffer layer using the mask pattern subjected tothe heat treatment to form the buffer layer having the uneven patternformed thereon.

In one embodiment, the forming of the buffer layer having the unevenpattern formed thereon comprises: forming the buffer layer on thesubstrate; forming an insulating layer on the buffer layer; forming amask pattern on the insulating layer; performing a heat treatment on thesubstrate having the mask pattern formed thereon such that at least aportion of the cross-section of the mask pattern is curved; etching theinsulating layer using the mask pattern subjected to the heat treatmentto form the insulating layer having an uneven pattern formed thereon;and etching the buffer layer using the insulating layer having theuneven pattern formed thereon to form the buffer layer having the unevenpattern formed thereon.

In one embodiment, the forming of the light-emitting structurecomprises: conformally forming a first conductive layer of a firstconductivity type along the buffer layer; conformally forming alight-emitting layer along the first conductive layer; forming a secondconductive layer of a second conductivity type on the light-emittinglayer; and patterning the second conductive layer, the light-emittinglayer, and the first conductive layer to form the light-emittingstructure including the second conductive pattern, the light-emittingpattern and the first conductive pattern, the width of the firstconductive pattern being larger than that of the second conductivepattern and the light-emitting pattern such that the first conductivepattern protrudes from the second conductive pattern and thelight-emitting pattern in a lateral direction. In one embodiment, thefirst electrode is formed on a protruding region of the first conductivepattern, and the second electrode is formed on the upper surface and/orthe side wall of the light-emitting structure.

In one embodiment, the forming of the first electrode and the secondelectrode comprises: forming the second electrode on the light-emittingstructure after the light-emitting structure is formed; bonding thesubstrate and a conductive substrate such that the second electrode isinterposed between the substrate and the conductive substrate; removingthe substrate; and forming the first electrode on the buffer layer. Inone embodiment, the forming of the first electrode on the buffer layercomprises: etching a portion of the buffer layer such that the firstconductive pattern is exposed; forming an ohmic layer on the exposedregion of the first conductive pattern; and forming the first electrodeon the ohmic layer. In one embodiment, the conductive substrate islarger than the substrate.

According to another aspect of the present invention, there is provideda method of manufacturing a light-emitting device using the method ofmanufacturing a light-emitting element according to the above aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the more particular description of preferred embodimentsof the invention, as illustrated in the accompanying drawings in whichlike reference characters refer to the same parts throughout thedifferent views. The drawings are not necessarily to scale, emphasisinstead being placed upon illustrating the principles of the invention.In the drawings, the thickness of layers and regions are exaggerated forclarity.

FIG. 1 is a cross-sectional view illustrating a light-emitting elementaccording to a first embodiment of the present invention.

FIGS. 2A to 2C are diagrams illustrating various shapes of a bufferlayer shown in FIG. 1.

FIG. 3 is a diagram illustrating the operation of the light-emittingelement according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a light-emitting element according to asecond embodiment of the present invention.

FIG. 5 is a diagram illustrating a light-emitting element according to athird embodiment of the present invention.

FIG. 6 is a diagram illustrating a light-emitting element according to afourth embodiment of the present invention.

FIG. 7 is a diagram illustrating the operation of the light-emittingelement according to the fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating a light-emitting element according to afifth embodiment of the present invention.

FIG. 9 is a diagram illustrating a light-emitting element according to asixth embodiment of the present invention.

FIGS. 10 and 11 are diagrams illustrating a light-emitting deviceaccording to the first embodiment of the present invention.

FIG. 12 is a diagram illustrating a light-emitting device according tothe second embodiment of the present invention.

FIG. 13 is a diagram illustrating a light-emitting device according tothe third embodiment of the present invention.

FIG. 14 is a diagram illustrating a light-emitting device according tothe fourth embodiment of the present invention.

FIG. 15 is a diagram illustrating a light-emitting device according tothe fifth embodiment of the present invention.

FIG. 16 is a diagram illustrating a light-emitting device according tothe sixth embodiment of the present invention.

FIGS. 17 to 18B are diagrams illustrating a light-emitting deviceaccording to a seventh embodiment of the present invention.

FIG. 19 is a diagram illustrating a light-emitting device according toan eighth embodiment of the present invention.

FIGS. 20 to 23 are diagrams illustrating light-emitting devicesaccording to ninth to twelfth embodiments of the present invention.

FIGS. 24 to 28 are diagrams illustrating intermediate steps of a methodof manufacturing the light-emitting element according to the firstembodiment of the present invention.

FIGS. 29 to 33 are diagrams illustrating intermediate steps of a methodof manufacturing the light-emitting element according to the fifthembodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of the presentinvention are shown. The present invention may, however, be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this description will be thorough and complete, and will fullyconvey the present invention to those skilled in the art. In thedrawings, the size and relative sizes of layers and regions may beexaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, it can be directly on the otherelement or layer or intervening elements or layers may be present. Incontrast, when an element is referred to as being “directly on” anotherelement or layer, there are no intervening elements or layers present.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. In the specification, the samecomponents are denoted by the same reference numerals.

Exemplary embodiments of the present invention are described herein withreference to cross-sectional illustrations that are schematicillustrations of idealized embodiments of the present invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments of the present invention shouldnot be construed as limited to the particular shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing. Thus, the regions illustrated in thefigures are schematic in nature and their shapes are not intended toillustrate the precise shape of a region and are not intended to limitthe scope of the present invention.

FIGS. 1 to 3 are diagrams illustrating a light-emitting elementaccording to a first embodiment of the present invention. Specifically,FIG. 1 is a cross-sectional view illustrating the light-emitting elementaccording to the first embodiment of the present invention, FIGS. 2A to2C are diagrams illustrating various shapes of a buffer layer shown inFIG. 1, and FIG. 3 is a diagram illustrating the operation of thelight-emitting element according to the first embodiment of the presentinvention. The light-emitting element according to the first embodimentof the present invention is a lateral type.

First, referring to FIG. 1, a light-emitting element 1 according to thefirst embodiment of the present invention includes a buffer layer 108that is formed on a substrate 100 and has an uneven pattern 109 formedthereon, and a light-emitting structure 110 that is formed on the bufferlayer 108. The light-emitting structure 110 includes a first conductivepattern 112 of a first conductivity type, a light-emitting pattern 114,and a second conductive pattern 116 of a second conductivity type formedin this order. A first electrode 140 is electrically connected to thefirst conductive pattern 112, and a second electrode 150 is electricallyconnected to the second conductive pattern 116.

Specifically, the buffer layer 108 is used as a seed layer for formingthe first conductive pattern 112, the light-emitting pattern 114, andthe second conductive pattern 116. The buffer layer 108 is also used toprevent a lattice mismatch between the substrate 100 and thelight-emitting structure 110. Therefore, the buffer layer 108 improvesthe quality characteristics of the light-emitting structure 110.

The buffer layer 108 may be formed of any material suitable to serve asa seed layer. For example, the buffer layer 108 may be formed ofIn_(x)Al_(y)Ga_(1-x-y))N (0≦x≦1 and 0≦y≦1), or Si_(x)C_(y)N_((1-x-y))0(0≦x≦1 and 0≦y≦1).

The buffer layer 108 determines the shapes of the first conductivepattern 112 and the light-emitting pattern 114. The uneven pattern 109is formed on the buffer layer 108, and the shapes of the firstconductive pattern 112 and the light-emitting pattern 114 may beadjusted depending on the shape of the uneven pattern 109. This isbecause the first conductive pattern 112 and the light-emitting pattern114 are conformally formed along the buffer layer 108 having the unevenpattern 109 formed thereon, which will be described below.

The uneven pattern 109 may include a plurality of patterns, and theplurality of patterns may be periodically repeated. For example, theuneven pattern 109 may be a line pattern shown in FIG. 2A, a meshpattern shown in FIG. 2B, or a dot pattern shown in FIG. 2C. However,the patterns shown in FIGS. 2A to 2C are illustrative, but notlimitative.

At least a portion of the cross-section of the uneven pattern 109 mayhave a curvature. For example, the uneven pattern 109 may have asemicircular shape, as shown in FIG. 2C.

The buffer layer 108 may be grown on the substrate 100 by, for example,MOCVD (metal organic chemical vapor deposition), liquid phase epitaxy,hydride vapor phase epitaxy, molecular beam epitaxy, or MOVPE (metalorganic vapor phase epitaxy).

The light-emitting structure 110 includes the first conductive pattern112 of the first conductivity type, the light-emitting pattern 114, andthe second conductive pattern 116 of the second conductivity type formedin this order.

The first conductive pattern 112, the light-emitting pattern 114, andthe second conductive pattern 116 may include In_(x)Al_(y)Ga_((1-x-y))N(0≦x≦1 and 0≦y≦1) (that is, various kinds of materials including GaN).That is, the first conductive pattern 112, the light-emitting pattern114, the second conductive pattern 116 may be formed of, for example,AlGaN or InGaN.

Next, the layers will be described in detail. The first conductivepattern 112 may be a first conductivity type (for example, an n type),and the second conductive pattern 116 may be a second conductivity type(for example, a p type). Alternatively, the first conductive pattern 112may be the second conductivity type (p type), and the second conductivepattern 116 may be the first conductivity type (n type).

In the light-emitting pattern 114, carriers (for example, electrons) ofthe first conductive pattern 112 are coupled to carries (for example,holes) of the second conductive pattern 116 to emit light. Although notspecifically shown in the drawings, the light-emitting pattern 114 mayinclude a well layer and a barrier layer. Since the well layer has aband gap that is smaller than that of the barrier layer, the carriers(electrons and holes) are collected and coupled in the well layer. Thelight-emitting layer 114 may be classified as a single quantum well(SQW) structure or a multiple quantum well (MQW) structure according tothe number of well layers. The single quantum well structure includesone well layer, and the multiple quantum well structure includesmultiple well layers. In order to adjust emission characteristics, atleast one of the well layer and the barrier layer may be doped with atleast one of B, P, Si, Mg, Zn, Se, and Al.

In particular, in the light-emitting element 1 according to the firstembodiment of the present invention, the first conductive pattern 112may be conformally formed along the buffer layer 108 having the unevenpattern 109 formed thereon, and the light-emitting pattern 114 may beconformally formed along the first conductive pattern 112. Therefore,the light-emitting pattern 114 is not flat, but is curved.

Assuming that the substrates 100 having the same size are used, the areaof a flat light-emitting pattern is larger than that of the curvedlight-emitting pattern 114. Since the amount of light emitted from alight-emitting element is proportional to the size of the light-emittingpattern, the amount of light emitted from the curved light-emittingpattern 114 is more than that of light emitted from the flatlight-emitting pattern. That is, the light-emitting element 1 accordingto the first embodiment of the present invention can increase theemission amount of light, without increasing the size of the substrate100.

Various methods may be used to curve the light-emitting pattern 114.However, a method of forming the uneven pattern 109 on the buffer layer108 and conformally forming the first conductive pattern 112 and thelight-emitting pattern 114 along the buffer layer 108 according to thisembodiment of the present invention is more preferable than thefollowing methods in terms of emission characteristics.

Specifically, an uneven pattern may be formed on the first conductivepattern, and the light-emitting pattern may be conformally formed alongthe first conductive pattern having the uneven pattern formed thereon.However, since a material that is generally used to form the firstconductive pattern (for example, GaN) is not easily removed by wetetching, the uneven pattern needs to be formed on the first conductivepattern by dry etching. Since the dry etching causes various defects inthe first conductive pattern, many defects may occur in thelight-emitting pattern grown by using the first conductive pattern. Thedefective light-emitting pattern has bad emission characteristics.

As another method, the uneven pattern may be directly formed on thelight-emitting pattern. Since a material that is generally used to formthe light-emitting pattern (for example, a multi-layer formed byalternately laminating InGaN and GaN layers) is similar to that used toform the first conductive pattern, dry etching is used to form theuneven pattern on the light-emitting pattern. Therefore, this methodalso causes many defects in the light-emitting pattern.

In contrast, in this embodiment, as described above, since the bufferlayer 108 serves as a seed layer or it is used to prevent the latticemismatch between the substrate 100 and the light-emitting structure 110,defects occurring in the buffer layer 108 do not have a great effect onthe emission characteristics. Therefore, it is more preferable toperform dry etching on the buffer layer 108 to form the uneven pattern109 on the buffer layer 108 than to form the uneven pattern on thelayers other than the buffer layer.

As shown in FIG. 1, the upper surface of the second conductive pattern116 may be flat, but the present invention is not limited thereto. Sincethe second conductive pattern 116 has a very small thickness (forexample, a thickness of 120 nm or less), the second conductive pattern116 may be formed in an uneven pattern that is similar to the unevenpattern 109 formed on the buffer layer 108.

As shown in FIG. 1, since the width of the first conductive pattern 112is larger than that of the second conductive pattern 116 and thelight-emitting pattern 114, a portion of the first conductive pattern112 may protrude in the lateral direction (that is, the first conductivepattern 112 may protrude from the second conductive pattern 116 or thelight-emitting pattern 114).

An insulating layer 120 is conformally formed along the profile of thelight-emitting structure 110, and is patterned such that a portion ofthe first conductive pattern 112 and a portion of the second conductivepattern 116 are exposed. The insulating layer 120 may include a siliconoxide film, a silicon nitride film, an aluminum oxide film, or analuminum nitride film. The insulating layer 120 may be formed by, forexample, PECVD (plasma enhanced chemical vapor deposition), thermaloxidation, electron beam deposition, or sputtering.

A first ohmic layer 131 and a first electrode 140 may be formed on thefirst conductive pattern 112 exposed from the insulating layer 120, anda second ohmic layer 132 and a second electrode 150 may be formed on thesecond conductive pattern 116 exposed from the insulating layer 120.That is, the first electrode 140 may be formed in a protruding region ofthe first conductive pattern 112, and the second electrode 150 may beformed on the upper surface of the light-emitting structure 110.

Each of the first ohmic layer 131 and the second ohmic layer 132 mayinclude at least one of ITO (indium tin oxide), zinc (Zn), zinc oxide(ZnO), silver (Ag), tin (Ti), aluminum (Al), gold (Au), nickel (Ni),indium oxide (In₂O₃), tin oxide (SnO₂), copper (Cu), tungsten (W), andplatinum (Pt). Each of the first electrode 140 and the second electrode150 may include at least one of indium tin oxide (ITO), copper (Cu),nickel (Ni), chrome (Cr), gold (Au), titanium (Ti), platinum (Pt),aluminum (Al), vanadium (V), tungsten (W), molybdenum (Mo), and silver(Ag).

FIG. 1 shows a lateral-type light-emitting element 1. Therefore, lightmay be emitted from the light-emitting structure 110 to the upper sideof FIG. 1 (that is, to the second conductive pattern 116). In order toensure an optical path, the second electrode 150 is formed at one sideof the second conductive pattern 116. Of course, the second electrode150 may have the shape shown in FIG. 1 as long as the second electrode150 has high transparency and does not shield light.

The substrate 100 may be formed of any material as long as the materialcan grow the first conductive pattern 112, the light-emitting pattern114, and the second conductive pattern 116. For example, the substrate100 may be an insulating substrate made of, for example, sapphire(Al₂O₃) or zinc oxide (ZnO), or a conductive substrate made of, forexample, silicon (Si), silicon carbide (SiC), or gallium nitride (GaN).

Although not shown in the drawings, a texture shape may be formed on thesurface of the second conductive pattern 116. The texture shape makes itpossible to increase the amount of light emitted from the light-emittingstructure 110, which results in an improvement in light emissionefficiency.

Next, the operation of the light-emitting element 1 according to thefirst embodiment of the present invention will be described withreference to FIG. 3.

When the first conductive pattern 112 is an n type and the secondconductive pattern 116 is a p type, a first bias BIAS(−) is applied tothe first conductive pattern 112 through the first electrode 140 and thefirst ohmic layer 131, and a second bias BIAS(+) is applied to thesecond conductive pattern 116 through the second electrode 150 and thesecond ohmic layer 132. On the other hand, when the second conductivepattern 116 is an n type and the first conductive pattern 112 is a ptype, the second bias BIAS(+) is applied to the first conductive pattern112 through the first electrode 140 and the first ohmic layer 131, andthe first bias BIAS(−) is applied to the second conductive pattern 116through the second electrode 150 and the second ohmic layer 132.

In this way, a forward bias is applied to the light-emitting structure110. The forward bias causes the light-emitting pattern 114 to emit alight component L1 to the outside.

FIG. 4 is a diagram illustrating a light-emitting element according to asecond embodiment of the present invention. The light-emitting elementaccording to the second embodiment of the present invention is a lateraltype.

Referring to FIG. 4, a light-emitting element 2 according to the secondembodiment of the present invention differs from that according to thefirst embodiment in that the second conductive pattern 116 has an unevenupper surface and is conformally formed along the light-emitting pattern114.

When the second conductive pattern 116 is an uneven surface, light canbe emitted from the light-emitting pattern 114 to the outside withoutbeing confined in the light-emitting structure 110.

As shown in FIG. 4, the second ohmic layer 132 may be conformally formedalong the second conductive pattern 116, and the upper surface of thesecond ohmic layer 132 may be flat. In addition, a region of the secondohmic layer 132 in which the second electrode 150 will be formed may beflat.

FIG. 5 is a diagram illustrating a light-emitting element according to athird embodiment of the present invention. The light-emitting elementaccording to the third embodiment of the present invention is a lateraltype.

Referring to FIG. 5, a light-emitting element 3 according to the thirdembodiment of the present invention differs from that according to thefirst embodiment in that the side wall of the light-emitting structure110 is inclined. When the side wall of the light-emitting structure 110is inclined, light can be emitted from the light-emitting pattern 114 tothe outside without being confined in the light-emitting structure 110.That is, light emission efficiency is improved. In particular, theamount of light emitted from the side wall of the light-emittingstructure 110 is increased.

FIG. 6 is a diagram illustrating a light-emitting element according to afourth embodiment of the present invention. FIG. 7 is a diagramillustrating the operation of the light-emitting element according tothe fourth embodiment of the present invention. The light-emittingelement according to the fourth embodiment of the present invention is aflip chip type.

Referring to FIG. 6, a light-emitting element 4 according to the fourthembodiment of the present invention includes a buffer layer 108 havingan uneven pattern 109 formed thereon and a light-emitting structure 110that is formed on the buffer layer 108 such that the side wall thereofis inclined. A second electrode 150 may be a reflecting electrode (whichis made of a material having high reflectance, such as silver (Ag) oraluminum (Al)), and the second electrode 150 may be formed on the uppersurface and the side wall of the light-emitting structure 110.

Therefore, as shown in FIG. 7, a light component L2 of the lightcomponents L2 and L3 generated from the light-emitting structure 110 isdirectly emitted to the substrate 100, and the light component L3 isreflected from the second electrode 150 to the substrate 100. As such,the second electrode 150 formed on the side wall of the light-emittingstructure 110 can increase the light emission efficiency of the flipchip-type light-emitting element 4.

Although not shown in the drawings, in the flip chip-type light-emittingelement, the side wall of the light-emitting structure may not beinclined, and the second electrode may be formed on only the uppersurface of the light-emitting structure.

FIG. 8 is a diagram illustrating a light-emitting element according to afifth embodiment of the present invention. The light-emitting elementaccording to the fifth embodiment of the present invention is a verticaltype.

Referring to FIG. 8, a light-emitting element 5 according to the fifthembodiment of the present invention includes a conductive substrate 200,a bowl-shaped second electrode 150 that is formed on the conductivesubstrate 200, a light-emitting structure 110 formed in the secondelectrode 150, a buffer layer 108 formed on the light-emitting structure110, and a first electrode 140 formed on the buffer layer 108. Inparticular, the uneven pattern 109 may be formed on the buffer layer108, and the second conductive pattern 116 may be conformally formedalong the buffer layer 108. In addition, the light-emitting pattern 114may be conformally formed along the second conductive pattern 116.

The second electrode 150 may be formed of a material having highreflectance, such as silver (Ag) or aluminum (Al). The reason why thesecond electrode 150 is formed of a material having high reflectance isto reflect light emitted from the light-emitting structure 110 from thesecond electrode 150 to the outside.

The second electrode 150 and the second conductive pattern 116 areelectrically connected to each other by the second ohmic layer 132.

Even though the second electrode 150 is formed on the side wall of thelight-emitting structure 110 (even though the second electrode 150surrounds the light-emitting structure 110), the second electrode 150does not electrically connect the first conductive pattern 112 and thesecond conductive pattern 116 (that is, the patterns are notshort-circuited) since the insulating layer 120 is formed between thesecond electrode 150 and the light-emitting structure 110. That is, theinsulating layer 120 can prevent a leakage current.

The buffer layer 108 is formed such that a portion of the firstconductive pattern 112 is exposed, and the first ohmic layer 131 isformed on the exposed region of the first conductive pattern 112. Thefirst electrode 140 is formed on the first ohmic layer 131. That is, thefirst electrode 140 and the first conductive pattern 112 areelectrically connected to each other by the first ohmic layer 131.

Although not shown in the drawings, after the entire buffer layer 108 isremoved, the first ohmic layer 131 and the first electrode 140 may beformed on the first conductive pattern 112.

The buffer layer 108 may have a resistance that is larger than that ofthe first conductive pattern 112. The reason is that the firstconductive pattern 112 is doped with a first conductive dopant, but thebuffer layer 108 is undoped. The first electrode 140 and the firstconductive pattern 112 may be electrically connected to each other bythe first ohmic layer 131 in order to transmit a voltage applied to thefirst electrode 140 to the first conductive pattern 112 with a smallvoltage drop.

The conductive substrate 200 may be formed of a conductive material. Forexample, the conductive substrate 200 may be formed of at least one ofsilicon, strained silicon (Si), silicon alloy, Si—Al, SOI(silicon-on-insulator), silicon carbide (SiC), silicon germanium (SiGe),silicon germanium carbide (SiGeC), germanium, germanium alloy, galliumarsenide (GaAs), indium arsenide (InAs), a group III-V semiconductor,and a group II-VI semiconductor.

An adhesive material layer 210 is formed between the substrate 200 andthe second electrode 150. The adhesive material layer 210 is used tobond the substrate 200 and the second electrode 150. The adhesivematerial layer 210 may be formed of a conductive material. For example,the adhesive material layer 210 may be a metal layer. The metal layermay include at least one of Au, Ag, Pt, Ni, Cu, Sn, Al, Pb, Cr, and Ti.That is, the metal layer may be a single layer formed of Au, Ag, Pt, Ni,Cu, Sn, Al, Pb, Cr, or Ti, a laminate thereof, or a composition thereof.For example, the metal layer may be an Au layer, an Au—Sn layer, or amultilayer formed by alternately laminating Au and Sn layers. Theadhesive material layer 210 may be formed of a material having areflectance that is lower than that of the second electrode 150.

In the drawings, the adhesive material layer 210 is shown to be formedalong the profile of the substrate 200, but the present invention is notlimited thereto. For example, the adhesive material layer 210 may beconformally formed on the second electrode 150 along the profile of thesecond electrode 150.

Although not shown in the drawings, a barrier layer may be formedbetween the second electrode 150 and the intermediate material layer210. The barrier layer prevents the damage of the second electrode 150that reflects light. The barrier layer may be a single layer made of Pt,Ni, Cu, Al, Cr, Ti, or W, a laminate thereof, or a composition thereof.For example, the barrier layer may be a multilayer formed by alternatelylaminating TiW and Pt layers.

FIG. 9 is a diagram illustrating a light-emitting element according to asixth embodiment of the present invention.

Referring to FIG. 9, a light-emitting element 6 according to the sixthembodiment of the present invention differs from that according to thefifth embodiment in that a protrusion 151 is formed on the bowl-shapedsecond electrode 150 and a groove 118 is formed in the light-emittingstructure 110 provided in the second electrode 150 so as to correspondto the protrusion.

For example, one side of the light-emitting structure 110 is the rightside of the protrusion 151 or the groove 118, and the other side thereofis the left side of the protrusion 151 or the groove 118. A pad patternof the first electrode 140 may be formed on the one side of thelight-emitting structure 110.

Next, light-emitting devices manufactured by using the light-emittingelements 1 to 6 will be described. For convenience of description, alight-emitting device using the light-emitting element 1 according tothe first embodiment of the present invention is shown in the drawings,but the scope of the present invention is not limited thereto. It shouldbe understood by those skilled in the art that the light-emitting devicecan be manufactured by using any of the light-emitting elements 1 to 5.

FIGS. 10 and 11 are diagrams illustrating a light-emitting deviceaccording to the first embodiment of the present invention.

Referring to FIGS. 10 and 11, the light-emitting device according to thefirst embodiment of the present invention includes a circuit board 300and the light-emitting element 1 formed on the circuit board 300.

The circuit board 300 includes a first wiring line 310 and a secondwiring line 320 that are electrically isolated from each other. Thefirst wiring line 310 and the second wiring line 320 are provided on onesurface of the circuit board 300.

The first wiring line 310 is electrically connected to the secondelectrode 150 of the light-emitting element 1, and the second wiringline 320 is electrically connected to the first electrode 140 of thelight-emitting element 1. Specifically, the first wiring line 310 andthe second electrode 150 may be connected to each other by a wire 318,and the second wiring line 320 and the first electrode 140 may beconnected to each other by a wire 328. That is, the wiring lines and theelectrodes may be connected to each other by wire bonding.

FIG. 12 is a diagram illustrating a light-emitting device according tothe second embodiment of the present invention.

Referring to FIG. 12, the light-emitting device according to the secondembodiment of the present invention differs from that according to thefirst embodiment in that the circuit board 300 includes through vias 316and 326.

Specifically, the first wiring line 310 and the second wiring line 320are formed on one surface of the circuit board 300 so as to beelectrically insulated from each other, and a third wiring line 312 anda fourth wiring line 322 are formed on the other surface of the circuitboard 300 so as to be electrically insulated from each other. The firstwiring line 310 and the third wiring line 312 are connected to eachother by the first through via 316, and the second wiring line 320 andthe fourth wiring line 322 are connected to each other by the secondthrough via 326.

FIG. 13 is a diagram illustrating a light-emitting device according tothe third embodiment of the present invention.

Referring to FIG. 13, the light-emitting device according to the thirdembodiment of the present invention differs from that according to thefirst embodiment in that it includes a phosphor layer 340 that surroundsthe light-emitting element 1 and a second transparent resin 350 thatsurrounds the phosphor layer 340.

The phosphor layer 340 may be a mixture of a first transparent resin 342and a phosphor 344. The phosphor 344 dispersed in the phosphor layer 340absorbs light emitted from the light-emitting element 1 and converts itinto light with a different wavelength. Therefore, as the phosphor isdispersed well, the emission characteristics are improved. As a result,the wavelength conversion efficiency and the color mixture effect of thephosphor 344 can be improved.

For example, the phosphor layer 340 may be formed in the light-emittingdevice in order to emit white light. When the light-emitting element 1emits blue light, the phosphor 344 may include a yellow phosphor, and itmay also include a red phosphor in order to improve a color renderingindex (CRI) characteristic. When the light-emitting element 1 emits UVlight, the phosphor 344 may include all of the red, green, and bluephosphors.

The first transparent resin 342 is not particularly limited as long asit can stably disperse the phosphor 344. For example, the firsttransparent resin 342 may be, for example, an epoxy resin, a siliconresin, a hard silicon resin, a modified silicon resin, a urethane resin,an oxetane resin, an acrylic resin, a polycarbonate resin, or apolyimide resin.

The phosphor 344 is not particularly limited as long as it can absorblight from the light-emitting structure 110 and convert it into lighthaving a different wavelength. For example, the phosphor is preferablyat least one selected from the following materials: a nitride-basedphosphor or an oxynitride-based phosphor that is mainly activated by alanthanoid element, such as Eu or Ce; an alkaline earth element halogenapatite phosphor, an alkaline earth metal element boride halogenphosphor, an alkaline earth metal element aluminate phosphor, alkalineearth element silicate, alkaline earth element sulfide, alkali earthelement thiogallate, alkaline earth element silicon nitride, andgermanate that are mainly activated by a lanthanoid element, such as Eu,or a transition metal element, such as Mn; rare earth aluminate and rareearth silicate that are mainly activated by a lanthanoid element, suchas Ce; and an organic compound and an organic complex that are mainlyactivated by a lanthanoid element, such as Eu. Specifically, thefollowing phosphors may be used, but the present invention is notlimited to thereto.

The nitride-based phosphors that are mainly activated by a lanthanoidelement, such as Eu or Ce include M₂Si₅N₈:Eu (M is at least one elementselected from the group consisting of Sr, Ca, Ba, Mg, and Zn). Inaddition to M₂Si₅N₈:Eu, MSi₇N₁₀:Eu, M_(1.8)Si₅O_(0.2)N₈:Eu,M_(0.9)Si₇O_(0.1)N₁₀:Eu (M is at least one element selected from thegroup consisting of Sr, Ca, Ba, Mg, and Zn) are also included.

The oxynitride-based phosphors mainly activated by a lanthanoid element,such as Eu or Ce, include MSi₂O₂N₂:Eu (M is at least one elementselected from the group consisting of Sr, Ca, Ba, Mg, and Zn).

The alkaline earth element halogen apatite phosphors mainly activated bya lanthanoid element, such as Eu, or a transition metal element, such asMn, include M₅(PO₄)₃X:R (M is at least one element selected from thegroup consisting of Sr, Ca, Ba, Mg, and Zn, X is at least one elementselected from the group consisting of F, Cl, Br, and I, and R is atleast one element selected from the group consisting of Eu, Mn, and acombination of Eu and Mn).

The alkaline earth metal element boride halogen phosphors includeM₂B₅O₉X:R (M is at least one element selected from the group consistingof Sr, Ca, Ba, Mg, and Zn, X is at least one element selected from thegroup consisting of F, Cl, Br, and I, and R is at least one elementselected from the group consisting of Eu, Mn, and a combination of Euand Mn).

The alkaline earth metal element aluminate phosphors include SrAl₂O₄:R,Sr₄Al₁₄O₂₅:R, CaAl₂O₄:R, BaMg₂Al₁₆O₂₇:R, and BaMgAl₁₀O₁₇:R(R is at leastone element selected from the group consisting of Eu, Mn, and acombination of Eu and Mn).

The alkaline earth sulfide-based phosphors include, for example,La₂O₂S:Eu, Y₂O₂S:Eu, and Gd₂O₂S:Eu.

The rare earth aluminate phosphors mainly activated by a lanthanoidelement, such as Ce, include YAG phosphors having the compositions ofY₃Al₅O₁₂:Ce, (Y_(0.8)Gd_(0.2))₃Al₅O₁₂:Ce, Y₃(Al_(0.8)Ga_(0.2))₅O₁₂:Ce,and (Y, Gd)₃(Al, Ga)₅O₁₂:Ce. The rare earth aluminate phosphors alsoinclude Tb₃Al₅O₁₂:Ce and Lu₃Al₅O₁₂:Ce in which a part or the whole of Yis substituted with, for example, Tb or Lu.

The alkaline earth element silicate phosphor may consist of silicate,and a representative example thereof is (SrBa)₂SiO₄:Eu.

Other phosphors include ZnS:Eu, Zn₂GeO₄:Mn, and MGa₂S₄:Eu (M is at leastone element selected from the group consisting of Sr, Ca, Ba, Mg, andZn, and X is at least one element selected from the group consisting ofF, Cl, Br and I).

The above-mentioned phosphors may include at least one element selectedfrom the group consisting of Tb, Cu, Ag, Au, Cr, Nd, Dy, Co, Ni, and Ti,instead of or in addition to Eu, if necessary.

Other phosphors having the same performance and effect as describedabove may also be used.

The second transparent resin 350 has a lens shape, and diffuses lightemitted from the light-emitting element 1. It is possible to adjust thediffusion and emission characteristics of the second transparent resinby controlling the curvature and the flatness of the second transparentresin 350. The second transparent resin 350 is formed so as to surroundthe phosphor layer 340, and protects the phosphor layer 340. The reasonis that, when the phosphor 344 contacts water, the characteristicsthereof deteriorate.

The second transparent resin 350 may be formed of any material that cantransmit light. For example, the second transparent resin 350 may beformed of an epoxy resin, a silicon resin, a hard silicon resin, amodified silicon resin, a urethane resin, an oxetane resin, an acrylicresin, a polycarbonate resin, or a polyimide resin.

FIG. 14 is a diagram illustrating a light-emitting device according tothe fourth embodiment of the present invention.

Referring to FIG. 14, the phosphor 344 is formed along the profiles ofthe light-emitting element 1 and the circuit board 300.

In this case, the phosphor 344 may be coated without a separate firsttransparent resin (see reference numeral 342 in FIG. 13).

When the phosphor 344 is coated without a separate first transparentresin, a single transparent resin layer surrounds the light-emittingelement 1 (that is, a single layer 350 without the first transparentresin 342).

FIG. 15 is a diagram illustrating a light-emitting device according tothe fifth embodiment of the present invention.

Referring to FIG. 15, the light-emitting device according to the fifthembodiment of the present invention differs from that according to thethird embodiment in that it includes the first transparent resin 342surrounding the light-emitting element 1, the phosphor 344 formed on thefirst transparent resin 342, and the second transparent resin 350 formedon the phosphor 344.

That is, since the first transparent resin 342 and the phosphor 344 areseparately coated, the phosphor 344 is conformally formed with a smallthickness along the surface of the first transparent resin 342.

FIG. 16 is a diagram illustrating a light-emitting device according tothe sixth embodiment of the present invention. The light-emitting deviceaccording to the sixth embodiment of the present invention is a top viewtype, but the present invention is not limited thereto.

Referring to FIG. 16, a sub-mount 41 having the light-emitting element 1mounted thereon is provided on a package body 211. Specifically, thepackage body 211 may include a slot 212 formed therein, and thesub-mount 41 having the light-emitting element 1 mounted thereon may beprovided in the slot 212. In particular, the side wall of the slot 212may be inclined. Light emitted from the light-emitting element 1 may bereflected from the side wall and then travel forward. The size of theslot 212 may be determined in consideration of the amount of light whichis emitted from the light-emitting element 1 and reflected from the sidewall of the slot 212, the reflection angle thereof, the kind oftransparent resin filling the slot 212, and the kind of phosphor. It ispreferable that the sub-mount 41 be arranged at the center of the slot212. When the distance between the light-emitting element 1 and the sidewall is constant, it is easy to prevent color irregularity.

The package body 211 may be formed of an organic material having highlight resistance, such as a silicon resin, an epoxy resin, an acrylicresin, a urea resin, a fluororesin, or an imide resin, or an inorganicmaterial having high light resistance, such as glass or silica gel. Inaddition, the package body 211 may be formed of a heat-resistant resinsuch that it is not melt by heat during a manufacturing process. Inaddition, in order to reduce the thermal stress of resin, variousfillers, such as aluminum nitride, aluminum oxide, and a compoundthereof, may be mixed with the resin. The material forming the packagebody 211 is not limited to resin. A portion (for example, the side wall)of or the entire package body 211 may be formed of a metal material or aceramic material. For example, when the entire package body 211 isformed of a metal material, it is easy to dissipate heat generated fromthe light-emitting element 1 to the outside.

In addition, leads 214 a and 214 b electrically connected to thelight-emitting element 1 are provided in the package body 211. Thelight-emitting element 1 may be electrically connected to the sub-mount41, and the sub-mount 41 and the leads 214 a and 214 b may be connectedto each other by, for example, vias. The leads 214 a and 214 b may beformed of a material having high thermal conductivity in order todirectly dissipate heat generated from the light-emitting element 1 tothe outside through the leads 214 a and 214 b.

Although not shown in the drawings, at least a portion of the slot maybe filled up with a transparent resin layer. A phosphor may be formed onthe transparent resin layer. Alternatively, the transparent resin layerand the phosphor may be mixed with each other.

For example, the phosphor may be used as follows in order to emit whitelight. When the light-emitting element 1 emits blue light, the phosphor344 may include a yellow phosphor, and it may also include a redphosphor in order to improve a color rendering index (CRI)characteristic. When the light-emitting element 1 emits UV light, thephosphor may include all of the red, green, and blue phosphors.

FIGS. 17 to 18B are diagrams illustrating a light-emitting deviceaccording to a seventh embodiment of the present invention.Specifically, FIGS. 17 to 18B are diagrams illustrating a light-emittingelement array including a plurality of light-emitting elements arrangedon a circuit board. Particularly, FIGS. 18A and 18B show examples of thearrangement of the phosphor layer 340 and the second transparent resin350 formed on the light-emitting element array.

Referring to FIG. 17, the first wiring lines 310 and the second wiringlines 320 extend in one direction on the circuit board 300. Thelight-emitting elements 1 are arranged on the first wiring lines 310 ina line along the direction in which the first wiring line 310 extends.

When first and second biases are respectively applied to the first andsecond wiring lines 310 and 320 and a forward bias is applied to thelight-emitting structure (not shown) in the light-emitting element 1,the light-emitting element 1 emits light.

Referring to FIG. 18A, the phosphor layer 340 and the second transparentresin 350 may be formed in linear shapes. For example, as shown in FIG.17, when the light-emitting elements 1 are arranged in the direction inwhich the first wiring line 310 extends, the phosphor layer 340 and thesecond transparent resin 350 may also extend in the direction in whichthe first wiring line 310 extends. Alternatively, the phosphor layer 340and the second transparent resin 350 may be formed so as to surround thefirst wiring line 310 and the second wiring line 320.

Referring to FIG. 18B, the phosphor layer 340 and the second transparentresin 350 may be formed in dot shapes. The phosphor layer 340 and thesecond transparent resin 350 may be formed so as to surround only thecorresponding light-emitting element 1.

FIG. 19 is a diagram illustrating a light-emitting device according toan eighth embodiment of the present invention.

FIG. 19 shows an end product to which the light-emitting deviceaccording to the eighth embodiment of the present invention is applied.The light-emitting devices according to the above-described embodimentsof the present invention may be applied to various apparatuses, such asilluminating devices, display devices, and mobile apparatuses (forexample, a mobile phone, an MP3 player, and a navigation system). Thedevice shown in FIG. 19 is an edge type backlight unit (BLU) used in aliquid crystal display (LCD). Since the liquid crystal display does nothave a light source therein, the backlight unit is used as a lightsource, and the backlight unit illuminates the rear surface of a liquidcrystal panel.

Referring to FIG. 19, the backlight unit includes the light-emittingelement 1, a light guide plate 410, a reflecting plate 412, a diffusionsheet 414, and a pair of prism sheets 416.

The light-emitting element 1 emits light. The light-emitting element 1may be a side view type.

The light guide plate 410 guides light to the liquid crystal panel 450.The light guide plate 410 is formed of a transparent plastic material,such as an acrylic resin, and guides light emitted from thelight-emitting device to the liquid crystal panel 450 that is providedabove the light guide plate 410. Therefore, various patterns 412 a thatchange the traveling direction of light incident on the light guideplate 410 to the liquid crystal panel 450 are printed on the rearsurface of the light guide plate 410.

The reflecting plate 412 is provided on the lower surface of the lightguide plate 410 to reflect light emitted from the lower side of thelight guide plate 410 to the upper side. The reflecting plate 412reflects light that is not reflected by the patterns 412 a, which areprovided on the rear surface of the light guide plate 410, to theemission surface of the light guide plate 410. In this way, it ispossible to reduce light loss and improve the uniformity of lightemitted from the emission surface of the light guide plate 410.

The diffusion sheet 414 diffuses light emitted from the light guideplate 410 to prevent partial light concentration.

Trigonal prisms are formed on the upper surface of the prism sheet 416in a predetermined array. In general, two prism sheets are arranged suchthat the prisms deviate from each other at a predetermined angle. Inthis way, the prism sheets make light diffused by the diffusion sheet414 travel in a direction that is vertical to the liquid crystal panel450.

FIGS. 20 to 23 are diagrams illustrating light-emitting devicesaccording to ninth to twelfth embodiments of the present invention.

FIGS. 20 to 23 show end products to which the above-mentionedlight-emitting device is applied. FIG. 20 shows a projector, FIG. 21shows a car headlight, FIG. 22 shows a streetlamp, and FIG. 23 shows alamp. The light-emitting element 1 used in FIGS. 20 to 23 may be a topview type.

Referring to FIG. 20, light emitted from a light source 410 passesthrough a condensing lens 420, a color filter 430, and a shaping lens440 and is then reflected from a digital micromirror device (DMD) 450.Then, the light reaches a screen 490 through a projection lens 480. Thelight-emitting element according to the above-described embodiments ofthe present invention is provided in the light source 410.

Next, a method of manufacturing the light-emitting elements according tothe above-described embodiments of the present invention will bedescribed.

FIGS. 24 to 28 are diagrams illustrating intermediate steps of a methodof manufacturing the light-emitting element according to the firstembodiment of the present invention.

First, referring to FIG. 24, a buffer layer 108 a is formed on thesubstrate 100.

Then, a mask pattern is formed on the buffer layer 108 a, and a heattreatment is performed on the substrate 100 having the mask patternformed thereon. At least a portion of the cross-section of the maskpattern 190 subjected to the heat treatment is curved.

Referring to FIG. 25, the buffer layer 108 a is etched by using the maskpattern 190 subjected to the heat treatment, thereby completing thebuffer layer 108 having the uneven pattern 109 formed thereon. In thiscase, dry etching is performed on the buffer layer 108 a, but thepresent invention is not limited thereto. For example, wet etching maybe used.

Although not shown in the drawings, an insulating film including asilicon oxide film, a silicon nitride film, an aluminum oxide film, oran aluminum nitride film may be formed on the buffer layer 108 a, andthe mask pattern 190 may be formed on the insulating film. Then, a heattreatment may be performed on the mask pattern 190 such that a portionof the cross-section of the mask pattern 190 is curved, and theinsulating film may be etched using the mask pattern 190 to form anuneven pattern on the insulating film. Then, the buffer layer 108 a isetched using the insulating film having the uneven pattern formedthereon, thereby completing the buffer layer 108 having the unevenpattern 109 formed thereon.

Referring to FIG. 26, a first conductive layer 112 a of a firstconductivity type is conformally formed along the buffer layer 108, anda light-emitting layer 114 a is conformally formed along the firstconductive layer 112 a. Then, a second conductive layer 116 of a secondconductivity type is formed on the light-emitting layer 114 a.

The first conductive layer 112 a, the light-emitting layer 114 a, andthe second conductive layer 116 a may be grown by, for example, MOCVD(metal organic chemical vapor deposition), liquid phase epitaxy, hydridevapor phase epitaxy, molecular beam epitaxy, or MOVPE (metal organicvapor phase epitaxy).

Referring to FIG. 27, the second conductive layer 116 a, thelight-emitting layer 114 a, and the first conductive layer 112 a arepatterned to form the light-emitting structure 110 including the secondconductive pattern 116, the light-emitting pattern 114, and the firstconductive pattern 112.

In this case, the width of the first conductive pattern 112 is largerthan that of the second conductive pattern 116 and the width of thelight-emitting pattern 114, such that the first conductive pattern 112protrudes from the second conductive pattern 116 and the light-emittingpattern 114 in the lateral direction.

Although not shown in the drawings, when the second conductive layer 116a, the light-emitting layer 114 a, and the first conductive layer 112 aare patterned, the light-emitting structure 110 may be formed such thatthe side wall thereof is inclined.

Referring to FIG. 28, the insulating layer 120 is formed on thelight-emitting structure 110 including the second conductive pattern116, the light-emitting pattern 114, and the first conductive pattern112.

Then, the insulating layer 120 is patterned to expose a portion of thefirst conductive pattern 112 and a portion of the second conductivepattern 116.

Referring to FIG. 1 again, the first ohmic layer 131 and the firstelectrode 140 are formed on the first conductive pattern 112 exposedfrom the insulating layer 120, and the second ohmic layer 132 and thesecond electrode 150 are formed on the second conductive pattern 116exposed from the insulating layer 120. In this way, the light-emittingelement 1 according to the first embodiment of the present invention iscompleted.

FIGS. 29 to 33 are diagrams illustrating a method of manufacturing thelight-emitting element according to the fifth embodiment of the presentinvention.

Referring to FIG. 29, a sacrificial layer 102 is formed on the substrate100. Specifically, the sacrificial layer 102 is used to remove thesubstrate 100 using a laser lift-off (LLO) method, which will bedescribed below. The sacrificial layer 102 may be, for example, a GaNlayer.

Then, the buffer layer 108 having the uneven pattern 109 formed thereonis formed of the sacrificial layer 102. The first conductive layer 112 aof a first conductivity type is conformally formed along the bufferlayer 108 having the uneven pattern 109 formed thereon, and thelight-emitting layer 114 a is conformally formed on the first conductivelayer 112 a. Then, the second conductive layer 116 a of a secondconductivity type is formed on the light-emitting layer 114 a.

Referring to FIG. 30, the second conductive layer 116 a, thelight-emitting layer 114 a, and the first conductive layer 112 a arepatterned to form the light-emitting structure 110 including the secondconductive pattern 116, the light-emitting pattern 114, and the firstconductive pattern 112. In this case, the light-emitting structure 110is formed such that the side wall thereof is inclined.

Then, the insulating layer 120 is formed on the upper surface and theside wall of the light-emitting structure 110, and a portion of theinsulating layer 120 is etched to expose a portion of the upper surfaceof the second conductive pattern 116.

Then, the second ohmic layer 132 is formed on the exposed secondconductive pattern 116.

Then, the second electrode 150 is formed on the upper surface and theside wall of the light-emitting structure 110.

Referring to FIG. 31, the substrate 100 is bonded to the conductivesubstrate 200.

Specifically, the conductive substrate 200 may be formed of at least oneof silicon, strained silicon (Si), silicon alloy, silicon aluminum(Si—Al), SOI (silicon-on-insulator), silicon carbide (SiC), silicongermanium (SiGe), silicon germanium carbide (SiGeC), germanium,germanium alloy, gallium arsenide (GaAs), indium arsenide (InAs), agroup III-V semiconductor, and a group II-VI semiconductor.

It is preferable that the substrate 100 or the conductive substrate 200be substantially flat. When the substrate 100 or the conductivesubstrate 200 is curved, it is difficult to bond the substrates. Sincean intermediate material layer 210 is interposed between the substrate100 and the conductive substrate 200 (particularly, when theintermediate material layer 210 has a sufficient thickness), theintermediate material layer 210 can compensate for the slight curvatureof the substrate 100 or the conductive substrate 200, which will bedescribed below.

For example, the conductive substrate 200 and a plurality of substrates100 may be bonded to each other by adhesive bonding, which will bedescribed in detail below.

First, the conductive substrate 200 and a plurality of substrates 100are cleaned. It is preferable that the bonding surface of the conductivesubstrate 200 and the bonding surfaces of the substrates 100 be wellcleaned. The reason is that various impurities adhered to the surfacesof the conductive substrate 200 and the substrates 100, such asparticles and dust, may be a contamination source. That is, if there areimpurities in an interface between the conductive substrate 200 and thesubstrates 100 during the bonding process therebetween, bonding energymay be weakened. When the bonding energy is weakened, the substrate 100is likely to be easily detached from the conductive substrate 200.

Then, the intermediate material layer 210 is formed on the bondingsurface of the conductive substrate 200 or the bonding surface of thesubstrate 100. In FIG. 31, for convenience of description, theintermediate material layer 210 is formed on the bonding surface of theconductive substrate 200. Although not shown in the drawings, anotherintermediate material layer 210 may be conformally formed along theprofile of the second electrode 150 of the substrate 100, or theintermediate material layer 210 may be formed on the upper surface ofthe second electrode 150 of the light-emitting structure 110 and thenbonded to the conductive substrate 200.

The intermediate material layer 210 may be formed of a conductivematerial. For example, the adhesive material layer 210 may be a metallayer. The metal layer may include at least one of Au, Ag, Pt, Ni, Cu,Sn, Al, Pb, Cr, and Ti. That is, the metal layer may be a single layerformed of Au, Ag, Pt, Ni, Cu, Sn, Al, Pb, Cr, or Ti, a laminate thereof,or a composition thereof. For example, the metal layer may be an Aulayer, an Au—Sn layer, or a multilayer formed by alternately laminatingAu and Sn layers. The intermediate material layer 210 may be formed of amaterial having a reflectance that is lower than that of the secondelectrode 150.

Although not shown in the drawings, a barrier layer may be formedbetween the second electrode 150 and the intermediate material layer210. The barrier layer prevents the damage of the second electrode 150that reflects light. The barrier layer may be a single layer made of Pt,Ni, Cu, Al, Cr, Ti, or W, a laminate thereof, or a composition thereof.For example, the barrier layer may be a multilayer formed by alternatelylaminating TiW and Pt layers.

Then, the second electrode 150 formed on the substrate 100 is arrangedso as to face the bonding surface of the conductive substrate 200. Thatis, the second electrode 150 is arranged between the substrate 100 andthe conductive substrate 200.

Then, a heat treatment is performed on the conductive substrate 200 andthe substrate 100. While the heat treatment is performed, the conductivesubstrate 200 and the substrate 100 may be bonded to each other bycompression.

When the intermediate material layer 210 is a single Au layer,thermocompression bonding may be performed at a temperature in the rangeof, for example, about 200° C. to 450° C. The temperature may beappropriately controlled by those skilled in the art.

However, in order to improve throughput, as shown in FIG. 32, when thesubstrate 100 and the conductive substrate 200 are bonded to each other,a plurality of substrates 100 may be bonded to one conductive substrate200.

Specifically, the conductive substrate 200 is larger than the substrate100. That is, when the conductive substrate 200 and the substrate 100overlap each other, the conductive substrate 200 covers the substrate100 so as to conceal the substrate 100. For example, when the conductivesubstrate 200 and the substrate 100 have circular shapes, the diameterof the conductive substrate 200 is larger than that of the substrate100. For example, the conductive substrate 200 may have a diameter of 6inches or more (about 150 mm or more), and the substrate 100 may have adiameter of less than 6 inches. When the conductive substrate 200 andthe substrate 100 have rectangular shapes, the diagonal of theconductive substrate 200 may be larger than that of the substrate 100.The second electrode 150 formed on each of the plurality of substrates100 is arranged so as to face the conductive substrate 200.

Referring to FIG. 33 again, the sacrificial layer 102 is peeled off toremove the substrate 100.

Specifically, the substrate 100 may be removed by a laser lift-off (LLO)process or a chemical lift-off (CLO) process.

For example, the LLO process is performed as follows.

A laser beam is radiated to the substrate 100. Since the laser beam hasa small spot, the substrate 100 is scanned by the laser beam. The laserbeam is used to remove the sacrificial layer 102. Then, the substrate100 is peeled off starting from a portion to which the laser beam isradiated.

In order to prevent the damage of the light-emitting element during thelaser lift-off process, the thickness of the substrate 100 may bereduced before the LLO process. As described above, since the substrate100 is peeled off starting from a portion to which the laser beam isradiated, the light-emitting structure 110 may be cracked or damaged dueto physical force when the substrate 100 is peeled off. However, if thethickness of the substrate 100 is reduced in advance by, for example, achemical mechanical polishing (CMP) process, the physical force when thesubstrate 100 is peeled off is weakened. Therefore, it is possible toprevent the damage of the light-emitting structure 110.

Referring to FIG. 8 again, the first electrode 140 is formed on thebuffer layer 108. In this way, the light-emitting element 5 according tothe fifth embodiment of the present invention is completed.

Specifically, a portion of the buffer layer 108 is etched such that thefirst conductive pattern 112 is exposed, and the first ohmic layer 131is formed on the exposed region of the first conductive pattern 112. Thefirst electrode 140 is formed on the first ohmic layer 131.

As described above, the buffer layer 108 may have a resistance that islarger than that of the first conductive pattern 112. The reason is thatthe first conductive pattern 112 is doped with a first conductivedopant, but the buffer layer 108 is undoped. The first ohmic layer 131is formed between the first electrode 140 and the first conductivepattern 112 in order to transmit a voltage applied to the firstelectrode 140 to the first conductive pattern 112 with a small voltagedrop.

A description of the methods of manufacturing the light-emittingelements according to the second to fourth embodiments will be omittedsince those skilled in the art can infer the methods from the methods ofmanufacturing the light-emitting elements according to the first andfifth embodiments of the present invention. In addition, a descriptionof a method of manufacturing light-emitting devices using thelight-emitting elements will be omitted since those skilled in the artcan infer the method from the above.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A light-emitting element comprising: a buffer layer having an unevenpattern formed thereon; a light-emitting structure including a firstconductive pattern of a first conductivity type that is conformallyformed along the buffer layer having the uneven pattern formed thereon,a light-emitting pattern that is conformally formed along the firstconductive pattern, and a second conductive pattern of a secondconductivity type that is formed on the light-emitting pattern; a firstelectrode electrically connected to the first conductive pattern; and asecond electrode electrically connected to the second conductivepattern.
 2. The light-emitting element of claim 1, wherein at least aportion of the cross-section of the uneven pattern is curved.
 3. Thelight-emitting element of claim 2, wherein the uneven pattern has asemicircular shape in a cross-sectional view.
 4. The light-emittingelement of claim 1, wherein the uneven pattern includes a plurality ofperiodic patterns.
 5. The light-emitting element of claim 1, wherein theuneven pattern is at least one of a dot pattern, a line pattern, and amesh pattern.
 6. The light-emitting element of claim 1, wherein thesecond conductive pattern is conformally formed along the light-emittingpattern.
 7. The light-emitting element of claim 1, wherein the secondconductive pattern has a flat upper surface.
 8. The light-emittingelement of claim 1, wherein the side wall of the light-emittingstructure is inclined.
 9. The light-emitting element of claim 1, whereinthe width of the first conductive pattern is larger than that of thesecond conductive pattern and the light-emitting pattern such that aportion of the first conductive pattern protrudes from the secondconductive pattern and the light-emitting pattern in a lateraldirection.
 10. The light-emitting element of claim 9, wherein the firstelectrode is formed on a protruding portion of the first conductivepattern, and the second electrode is formed on the upper surface and/orthe side wall of the light-emitting structure.
 11. The light-emittingelement of claim 1, wherein the second electrode is a reflectingelectrode, and the second electrode is formed on the upper surface andthe side wall of the light-emitting structure.
 12. A light-emittingelement comprising: a conductive substrate; a first electrode having abowl shape and formed on the conductive substrate; a light-emittingstructure including a first conductive pattern of a first conductivitytype, a light-emitting pattern, and a second conductive pattern of asecond conductivity type sequentially formed in the first electrode; abuffer layer formed on the light-emitting structure; and a secondelectrode formed on the buffer layer, wherein an uneven pattern isformed on the buffer layer, the second conductive pattern is conformallyformed along the buffer layer, and the light-emitting pattern isconformally formed along the second conductive pattern.
 13. Thelight-emitting element of claim 12, wherein at least a portion of thecross-section of the uneven pattern is curved.
 14. The light-emittingelement of claim 12, wherein the buffer layer is formed such that aportion of the second conductive pattern is exposed, an ohmic layer isformed on the exposed region of the second conductive pattern, and thesecond electrode is formed on the ohmic layer.
 15. The light-emittingelement of claim 12, wherein the bowl-shaped first electrode includes aprotrusion that protrudes from the lower side thereof, thelight-emitting structure is divided into two sides by the protrusion,and the second electrode is formed on one side of the light-emittingstructure.
 16. A light-emitting device comprising the light-emittingelement according to claim
 1. 17. A light emitting element comprising: asubstrate; a light emitting structure on the substrate, wherein thelight emitting structure comprises: a first conductive layer of P-typematerial comprising A1GaN; a light emitting layer on the firstconductive layer, wherein the light emitting layer comprises a multiplequantum well structure; and a second conductive layer of N-type materialon the light emitting layer, wherein the second conductive layer has anuneven surface pattern thereon and wherein the second conductive layercomprises InGaN; an insulating layer between the substrate and the firstconductive layer, said insulating layer having at least one openingtherethrough, wherein first and second biases are respectively appliedto the first and second conductive layers through the at least oneopening; a first metal layer electrically connected through the at leastone opening to the first conductive layer, wherein the first metal layercomprises an Ag layer and an Au layer; and a second metal layerelectrically connected through the at least one opening to the secondconductive layer, wherein the second metal layer comprises Al and Au.18. The light emitting element of claim 17, wherein the insulating layercomprises silicon nitride.
 19. The light emitting element of claim 18,further comprising a phosphor layer.
 20. The light emitting element ofclaim 19, further comprising a first transparent resin layer surroundingthe phosphor layer.
 21. The light emitting element of claim 20, whereinthe first transparent resin layer comprises a silicon resin.
 22. Thelight emitting element of claim 21, further comprising a secondtransparent resin layer surrounding the first transparent resin layer.23. The light emitting element of claim 22, wherein the secondtransparent resin layer has a lens shape.
 24. The light emitting elementof claim 23, wherein the second transparent resin layer comprises asilicon resin.
 25. The light emitting element of claim 17, wherein thelight emitting element is of a flip-chip type.